The Primary Breast Cancer Therapy Group (NSABP) was established in 1958. The objectives of the cooperative group remain as originally defined and are being expanded. They have been: (a) to evaluate the efficacy of various modalities employed in the treatment of primary breast cancer, (b) to estimate the worth of new and promising surgical adjuvant therapies, and (c) to gather biologic and other pertinent data from patients with such tumors. The present application is submitted so that we may continue our efforts directed toward these objectives. In addition, this grant will have as its prime objective the enhancement of the multidisciplinary aspects of the NSABP so that it may more effectively implement protocols utilizing multidisciplinary therapy for the treatment of primary breast cancer and other solid tumors, i.e., colo-rectal carcinoma. Funding for this grant will also permit the continued follow-up of about 3000 patients on existing primary breast cancer protocols and the the beginning of 5 new protocols directed toward Stages I, II and III breast cancer as well as protocols for evaluation of therapy in colo-rectal cancer. The breast cancer protocols to be implemented are: (a) Protocol 6: a trial to compare the worth of segmental mastectomy with and without breast radiation with total mastectomy plus axillary dissection. All patients with positive axillary nodes will receive adjuvant chemotherapy, (b) Protocol 8: a trial to compare the worth of three-drug chemotherapy, i.e., L-PAM, 5-FU and methotrexate, with two-drug chemotherapy, i.e., L-PAM an 5-FU, (c) Protocol 9: a trial to determine whether the anti-estrogen tamoxifen when combined with chemotherapy improves the results of chemotherapy alone, (d) Protocol 10: a trial to compare the value of the immunopotentiator C. parvum combined with chemotherapy vs. chemotherapy alone, and (e) protocol 11: a trial to evaluate various treatment modalities in the management of patients with clinical Stage III breast cancer.